provider-ephemeral-resources

Original：🇺🇸 English

Translated

Implement Terraform provider ephemeral resources with the Plugin Framework: the Open/Renew/Close lifecycle, ephemeral schema design, registration via EphemeralResources, renewal for expiring credentials, and how ephemeral values flow into write-only attributes and provider configuration. Use when adding an ephemeral resource, exposing secrets/tokens/certificates that must never persist in state or plan, deciding between an ephemeral resource and a data source, or wiring short-lived credentials from one provider into another.

5installs

Sourcehashicorp/agent-skills

Added on2026-08-12

NPX Install

npx skill4agent add hashicorp/agent-skills provider-ephemeral-resources

SKILL.md Content

View Translation Comparison →

Terraform Provider Ephemeral Resources

Ephemeral resources (Terraform 1.10+) produce values that are never persisted to state or plan. They exist for exactly one job: handing secrets — tokens, generated passwords, short-lived certificates, decrypted values — to the parts of a configuration that need them, without writing them to disk. Any data source that returns a sensitive value is a candidate to be (or to also exist as) an ephemeral resource.

Official docs: Ephemeral Resources.

When to Use One

Situation	Use
Read-only lookup of non-sensitive data	Data source
Value is sensitive and only needed at apply time (DB password for a provider block, token for a write-only attribute)	Ephemeral resource
Sensitive value that downstream managed resources must store (e.g. as an attribute)	Regular resource/data source — but pair with write-only attributes where possible
Credential that expires mid-operation (STS-style tokens, short-TTL leases)	Ephemeral resource with `Renew`

Ephemeral results can be used in provider configuration, write-only attributes, provisioner configuration, and other ephemeral contexts — but not in regular attributes, because those persist to state.

Lifecycle

Terraform calls up to three methods per operation:

Open
(required) — fetch or create the value; runs during plan and/or apply whenever the result is needed. There is no state to refresh and nothing to import.
Renew
(optional) — called when the wall clock passes the
```
RenewAt
```
returned by
```
Open
```
/
```
Renew
```
, for values that expire while Terraform is still running. Renew cannot return a new result — it can only extend/refresh what
```
Open
```
produced (e.g. re-lease the same credential); if the value itself changes on renewal, the API is not renewable in this sense and
```
Open
```
must return a longer-lived value.
Close
(optional) — called when Terraform is done with the value; revoke leases or delete temporary credentials here.

Open

can pass bytes forward via

resp.Private

;

Renew

and

Close

receive them — use this for lease IDs needed to renew/revoke.

Implementation

go

var (
    _ ephemeral.EphemeralResource              = &tokenEphemeralResource{}
    _ ephemeral.EphemeralResourceWithConfigure = &tokenEphemeralResource{}
    _ ephemeral.EphemeralResourceWithRenew     = &tokenEphemeralResource{}
    _ ephemeral.EphemeralResourceWithClose     = &tokenEphemeralResource{}
)

func NewTokenEphemeralResource() ephemeral.EphemeralResource {
    return &tokenEphemeralResource{}
}

type tokenEphemeralResource struct {
    client *examplecloud.Client
}

type tokenEphemeralResourceModel struct {
    RoleName types.String `tfsdk:"role_name"`
    Token    types.String `tfsdk:"token"`
    LeaseID  types.String `tfsdk:"lease_id"`
}

func (r *tokenEphemeralResource) Metadata(_ context.Context, req ephemeral.MetadataRequest, resp *ephemeral.MetadataResponse) {
    resp.TypeName = req.ProviderTypeName + "_token"
}

func (r *tokenEphemeralResource) Schema(_ context.Context, _ ephemeral.SchemaRequest, resp *ephemeral.SchemaResponse) {
    resp.Schema = schema.Schema{
        Attributes: map[string]schema.Attribute{
            "role_name": schema.StringAttribute{
                Required:            true,
                MarkdownDescription: "Role to obtain a token for.",
            },
            "token": schema.StringAttribute{
                Computed:            true,
                Sensitive:           true,
                MarkdownDescription: "The issued token. Never persisted to state.",
            },
            "lease_id": schema.StringAttribute{
                Computed:            true,
                MarkdownDescription: "Identifier of the token lease.",
            },
        },
    }
}

func (r *tokenEphemeralResource) Open(ctx context.Context, req ephemeral.OpenRequest, resp *ephemeral.OpenResponse) {
    var data tokenEphemeralResourceModel
    resp.Diagnostics.Append(req.Config.Get(ctx, &data)...)
    if resp.Diagnostics.HasError() {
        return
    }

    lease, err := r.client.IssueToken(ctx, data.RoleName.ValueString())
    if err != nil {
        resp.Diagnostics.AddError(
            "Error opening Token",
            fmt.Sprintf("issuing token for role (%s): %s", data.RoleName.ValueString(), err),
        )
        return
    }

    data.Token = types.StringValue(lease.Token)
    data.LeaseID = types.StringValue(lease.ID)

    resp.RenewAt = lease.ExpiresAt.Add(-2 * time.Minute) // renew with margin
    resp.Private.SetKey(ctx, "lease_id", []byte(lease.ID))
    resp.Diagnostics.Append(resp.Result.Set(ctx, &data)...)
}

func (r *tokenEphemeralResource) Renew(ctx context.Context, req ephemeral.RenewRequest, resp *ephemeral.RenewResponse) {
    leaseID, diags := req.Private.GetKey(ctx, "lease_id")
    resp.Diagnostics.Append(diags...)
    if resp.Diagnostics.HasError() {
        return
    }

    lease, err := r.client.RenewLease(ctx, string(leaseID))
    if err != nil {
        resp.Diagnostics.AddError("Error renewing Token", err.Error())
        return
    }
    resp.RenewAt = lease.ExpiresAt.Add(-2 * time.Minute)
}

func (r *tokenEphemeralResource) Close(ctx context.Context, req ephemeral.CloseRequest, resp *ephemeral.CloseResponse) {
    leaseID, diags := req.Private.GetKey(ctx, "lease_id")
    resp.Diagnostics.Append(diags...)
    if resp.Diagnostics.HasError() {
        return
    }

    if err := r.client.RevokeLease(ctx, string(leaseID)); err != nil {
        resp.Diagnostics.AddError("Error closing Token", err.Error())
    }
}

Configure

follows the same ProviderData-cast pattern as resources (the

provider-resources

skill, if available, shows it); the client comes from

resp.EphemeralResourceData

set in the provider's

Configure

.

Registration

The provider opts in via

provider.ProviderWithEphemeralResources

:

go

var _ provider.ProviderWithEphemeralResources = &examplecloudProvider{}

func (p *examplecloudProvider) EphemeralResources(_ context.Context) []func() ephemeral.EphemeralResource {
    return []func() ephemeral.EphemeralResource{
        NewTokenEphemeralResource(),
    }
}

Set

resp.EphemeralResourceData = client

in the provider's

Configure

alongside

ResourceData

/

DataSourceData

.

Design Rules

Never log the value, never put it in a diagnostic. The whole point is non-persistence; an error message containing the token defeats it.
Mark the secret attribute
```
Sensitive: true
```
anyway — it guards rendering in the ephemeral value's own lifecycle output.
No plan modifiers, no import, no
```
id
```
convention — there is no state for any of them to act on.
Schema inputs follow the same rules as data source arguments; expose the API's identifiers (
```
role_name
```
), not invented ones.
Set
```
RenewAt
```
with a safety margin before the real expiry; Terraform renews lazily, not on a precise timer.
If the upstream value cannot be revoked, skip
```
Close
```
rather than implementing a no-op that suggests revocation happens.

Testing

Ephemeral results never reach state, so tests assert them indirectly — the standard pattern echoes the ephemeral value through the

echoprovider

into a regular resource the test can inspect. Minimum coverage: a basic open-and-use test and per-attribute tests alongside required fields. Use the

provider-test-patterns

skill (if available) — its ephemeral testing reference covers the echoprovider setup, version gating (

tfversion.SkipBelow(tfversion.Version1_10_0)

), and multi-step patterns.

Documentation

Registry docs live at

docs/ephemeral-resources/<name>.md

, generated by

tfplugindocs

like every other page type. Use the

provider-docs

skill (if available) for the workflow; document the renewal/revocation behavior explicitly — users need to know whether closing their Terraform run revokes the credential.

Checklist

Value genuinely must not persist (otherwise a data source is simpler)
```
Open
```
implemented;
```
Renew
```
/
```
Close
```
only where the API supports them
Secret attributes
```
Sensitive: true
```
; value never logged or in diagnostics
Lease/handle passed via
```
Private
```
, not via the result
```
RenewAt
```
set with margin for expiring credentials

Registered in

EphemeralResources()

;

EphemeralResourceData

set in provider Configure

Echo-provider acceptance tests, version-gated to Terraform >= 1.10
Docs page explains lifetime, renewal, and revocation behavior